Xtensa relocation: some types not implemented

[redfast00]

I'm currently reverse engineering the ESP32 wifi and phy binary blobs (see also https://github.com/esp32-open-mac/ and the 38c3 talk about this https://media.ccc.de/v/38c3-liberating-wi-fi-on-the-esp32). They have some relocation types that are not currently handled:

• R_XTENSA_SLOT0_OP
• R_XTENSA_32 (apparently already implement, my bad, I was running an old version)
• R_XTENSA_ASM_EXPAND

It appears that the Linux kernel contains an implementation of these (https://github.com/torvalds/linux/blob/56e6a3499e14716b9a28a307bb6d18c10e95301e/arch/xtensa/kernel/module.c#L77); it would be nice if at least the three missing relocation types could be implemented.

[redfast00]

(related to #6138)

@mumbel I saw that you worked on other Xtensa relocations; thank you for that :D would you be willing to work on the other relocation types that are currently unimplemented?

[mumbel]

R_XTENSA_SLOT{0..14}_OP and R_XTENSA_ASM_EXPAND can probably be ignored and marked as SKIPPED.

doing some of the relocations (this is probably true on many/all arch) on unlinked .a files is just weird/impossible for this kind of analysis

Did you notice issues or just saw the bookmarks/prints that they were not supported (specific binary and address if so, i dont mind taking a look)?
but looking at https://github.com/jcmvbkbc/xtensa-abi/blob/master/relocations
they appear to be no-op, so ld would fix them while linking most likely and I think they should just be correct as is for ghidra.

[redfast00]

I noticed the warning that some relocations were missing; I thought it might be better to work on the unlinked file instead of the linked file (this is what I was doing before).

Here's the file: libphy.a.zip